1. Field of the Invention
The present invention relates to an electrophotographic type image forming apparatus such as a copying machine and a printer and, more particularly, to removing members for removing developing agents on an image bearing member.
2. Description of the Related Art
In recent years, in view of improvement of the quality of printed images, there has been a need for stabilization of the ability of cleaning members to remove developing agents from image bearing members.
Therefore, there have been used electrostatic cleaning members which capture and remove developing agents by being biased, as described in Japanese Patent Application Laid-open No. 2002-207403. Such electrostatic cleaning members are less prone to degrade their removing abilities due to wear of the cleaning members themselves and thus have stable removing abilities. In this case, some developing agents on the image bearing member bear smaller amount of electrical charges. Such developing agents are difficult to sufficiently remove with electrostatic cleaning members. Therefore, in order to compensate the removing ability of such electrostatic cleaning members, a contact-type cleaning member for removing developing agents from the image bearing member by contacting therewith is provided downstream side of the electrostatic cleaning members in the direction of the rotation of the image bearing member.
However, if the biases applied to the electrostatic cleaning members are interrupted, the developing agents captured by the electrostatic cleaning members will lose the constraint forces. Consequently, the developing agents captured by the electrostatic cleaning members will be adhered to the image bearing member, again. The developing agents moved from the electrostatic cleaning members to the image bearing member will be captured by the contact-type cleaning means and, at this time, the amount of the developing agents will be excessive for the contact-type cleaning member. This will cause the contact-type cleaning member to rub the developing agents on the image bearing member, contrary to the inherent effect of the contact-type cleaning member. It is difficult to properly form images on the regions having developing agents rubbed thereon, which may cause image failures.